I found a breakdown on Kolb on pro football focus, Kevin Kolb: Schaub-like or Feely-ish? .
I think it's pretty interesting.
I would say that the conclusion follows my thought on Kolb as well. I just don't know if he's a good quarterback or not. He did have the Dallas game where he was playing with scrubs, but he also seemed to do better on games where he was starting and was prepared.
However, the Cards will still have a sub-par or average at best offensive line. I don't think the price to get Kolb is worth this much uncertainty.
I'm feeling that the price of Orton is more reasonable and will have the same upside. Keep in mind the large pay raise that Kolb will be expecting as well. That is not a throwaway factor, large salary plus the price in draft picks/players, I don't think it adds up.